1. Field of the Invention
This invention is directed to a projection lens system for the projection of apparent 3-dimensional images from film, such as movie film, and includes structure for improving the life of such a system.
2. Description of the Prior Art
The production of images which give the impression of 3-dimensional depth have been the subject of considerable interest and accomplishment over the years for photography. The original stereopticon set forth the basic requirement: two images separately seen by the two eyes and differing in detail to give the impression of a 3-dimensional structure.
In projection systems for 3-dimensional imaging, coding of the overlapped images on the screen is required to permit the viewer's eyes to see the two images separately to obtain the 3-dimensional effect. Early coding was done with color, with one of the images coded with red, and the other blue so that red and blue filters in front of the respective eyes would separate the images for separate interpretation. An advantage of that system is that no special projector is needed. One color film can contain all of the information on one frame. The tremendous disadvantage of not being able to project images with colors of reality prevented such a system from being any more than a novelty.
Present-day polarizers have overcome that difficulty so that full color stereo images can be projected, and polarized binocular viewing devices can be employed for separating the images. This invention is directed to a projection lens system of improved life for the projection of movie images.